Their retreat comes in response to an ultimatum issued by al-Nusra Front earlier this week. Nusra Front, a powerful rival, blames ISIS for the death of Abu Khaled al-Suri, a senior Islamist commander, and threatened to expel ISIS from Syria if it did not appear before an Islamic court.

“ISIS has withdrawn from Aazaz, its most important bastion in Aleppo province, as well as the Minnigh military airport, the Mayer region and the villages of Deir Jamal and Kafin,” said the Syrian Observatory for Human Rights.